1. The Field of the Invention
This invention relates generally to the field of electrical connector systems for electrical components. In particular, embodiments of the present invention relate to a latching system that is particularly useful for use with low profile, user-removable, electronic modules that interface with a port of a host device. For example, embodiments of the present invention may find particular use with opto-electronic transceiver modules used to interface a host device with an optical communications network.
2. The Relevant Technology
Fiber optics are increasingly used for transmitting voice and data signals. As a transmission medium, light provides a number of advantages over traditional electrical communication techniques. For example, light signals allow for extremely high transmission rates and very high bandwidth capabilities. Also, light signals are resistant to electromagnetic interferences that would otherwise interfere with electrical signals. Light also provides a more secure signal because it doesn't allow portions of the signal to escape from the fiber optic cable as can occur with electrical signals in wire-based systems. Light also can be conducted over greater distances without the signal loss typically associated with electrical signals on copper wire.
While optical communications provide a number of advantages, the use of light as a transmission medium presents a number of implementation challenges. In particular, the data carried by light signal must be converted to an electrical format when received by a device, such as a network switch. Conversely, when data is transmitted to the optical network, it must be converted from an electronic signal to a light signal. A number of protocols define the conversion of electrical signals to optical signals and transmission of those optical, including the ANSI Fibre Channel (FC) protocol. The FC protocol is typically implemented using a transceiver module at both ends of a fiber optic cable. Each transceiver module typically contains a laser transmitter circuit capable of converting electrical signals to optical signals, and an optical receiver capable of converting received optical signals back into electrical signals.
Typically, a transceiver module is electrically interfaced with a host device—such as a host computer, switching hub, network router, switch box, computer I/O and the like—via a compatible connection port. Moreover, in some applications it is desirable to miniaturize the physical size of the transceiver module to increase the port density, i.e., and therefore accommodate a higher number of network connections within a given physical space. In addition, in many applications, it is desirable for the module to be hot-pluggable, which permits the module to be inserted and removed from the host system without removing electrical power. To accomplish many of these objectives, international and industry standards have been adopted that define the physical size and shape of optical transceiver modules to insure compatibility between different manufacturers. For example, in 1998, a group of optical manufacturers developed a set of standards for optical transceiver modules called the Small Form-factor Pluggable (“SFP”) Transceiver MultiSource Agreement (“MSA”). In addition to the details of the electrical interface, this standard defines the physical size and shape for the SFP transceiver modules, and the corresponding host port, so as to insure interoperability between different manufacturers' products. The standard also specifies that the module be hot-pluggable. To do so, the standard specifies that a user provide a minimum amount of space between host ports, so that transceiver modules can be individually accessed and removed from the host device without disturbing the adjacent modules and/or cable connections.
While such standards may recommend that there be a minimum distance between adjacent ports, there is often a desire to provide configurations having a higher port density. However, providing a high port density can be at odds with the ability to provide a module that complies with existing standards—i.e., that has a small form-factor and is hot-pluggable. In particular, previously existing module designs present a size and profile that mandates that a specific minimum amount of space be provided between host ports so that individual modules can be accessed and removed without disturbing an adjacent module and/or an adjacent fiber cable. Such modules either cannot be used in a device having a high port density (due to the space requirements), or, if used in such an environment, require the use of a special extraction tool to allow for access and retrieval of a module without disturbing adjacent modules and/or cables. Use of an extraction tool is often not desirable because it raises costs, can be misplaced, and may not be compatible with other module designs.
Therefore, there is a need for a module, such as an optical transceiver module, that utilizes a latching scheme that allows the module to maintain its small form factor and that still complies with existing standards. At the same time, the latching scheme should allow the module to be easily inserted and extracted from a port without the need for a special extraction tool. Moreover, extraction should be possible in a manner that does not disturb the communications link of adjacent modules, i.e., extraction should be achieved without inadvertently removing an adjacent module and/or fiber cable, even in a host having high port density. Such a module would allow host systems to provide a higher packing density, and yet allow the use of small form factor transceiver modules that comply with existing standards.